Parton energy loss in heavy-ion collisions via direct-photon and charged-particle azimuthal correlations

Scientific paper - Original scientific paper

• Author: B. I. Abelev
• Author: ...
• Author: Mirko Planinić
• Author: ...
• Author: Nikola Poljak
• Author: ...
• Author: J. X. Zuo
• Collaboration: STAR Collaboration
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

Charged-particle spectra associated with direct photon (γdir) and π0 are measured in p+p and Au+Au collisions at center-of-mass energy √sNN=200 GeV with the STAR detector at the Relativistic Heavy Ion Collider. A shower-shape analysis is used to partially discriminate between γdir and π0. Assuming no associated charged particles in the γdir direction (near side) and small contribution from fragmentation photons (γfrag), the associated charged-particle yields opposite to γdir (away side) are extracted. In central Au+Au collisions, the charged-particle yields at midrapidity (|η|<1) and high transverse momentum (3<pTassoc<16 GeV/c) associated with γdir and π0 (|η|<0.9, 8<pTtrig<16 GeV/c) are suppressed by a factor of 3–5 compared with p+p collisions. The observed suppression of the associated charged particles is similar for γdir and π0 and independent of the γdir energy within uncertainties. These measurements indicate that, in the kinematic range covered and within our current experimental uncertainties, the parton energy loss shows no sensitivity to the parton initial energy, path length, or color charge.

• Keywords (english): p p; interaction gold charged particle; yield parton; energy loss photon; direct production pi0; hadroproduction charged particle; associated production angular correlation; (charged particle photon) angular correlation; (charged particle pi0) transverse momentum; dependence heavy ion; scattering Brookhaven RHIC Coll parton; path length STAR 200 GeV-cms/nucleon
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical Review C - Nuclear Physics
• Numbering: vol. 82, no. 3, 034909
• p-ISSN: 0556-2813
• e-ISSN: 1089-490X
• DOI: https://doi.org/10.1103/PhysRevC.82.034909
• URN:NBN: urn:nbn:hr:217:412845
• Publication: 2010
• Project: Number: 119-0982887-1006; Title (croatian): Istraživanje hadronskih sustava upotrebom relativističkih projektila; Leader: Mirko Planinić; Jurisdiction: Croatia; Funding stream: ZP
• Document URL: http://link.aps.org/doi/10.1103/PhysRevC.82.034909
• Type of resource: Text
• Access conditions: Open access
• Public note: Copyright (2010) by the American Physical Society. Received 9 December 2009; published 30 September 2010.
• Created on: 2019-11-03 16:29:42